ClickHouse/docs/en/faq/index.md

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ClickHouse F.A.Q

This section of the documentation is a place to collect answers to ClickHouse-related questions that arise often.

Categories:

• General
  • What is ClickHouse?
  • Why ClickHouse is so fast?
  • Who is using ClickHouse?
  • What does “ClickHouse” mean?
  • What does “Не тормозит” mean?
  • What is OLAP?
  • What is a columnar database?
  • Why not use something like MapReduce?
• Use Cases
  • Can I use ClickHouse as a time-series database?
  • Can I use ClickHouse as a key-value storage?
• Operations
  • Which ClickHouse version to use in production?
  • Is it possible to delete old records from a ClickHouse table?
• Integration
  • How do I export data from ClickHouse to a file?
  • What if I have a problem with encodings when connecting to Oracle via ODBC?

{## TODO Question candidates:

• How to choose a primary key?
• How to add a column in ClickHouse?
• Too many parts
• How to filter ClickHouse table by an array column contents?
• How to insert all rows from one table to another of identical structure?
• How to kill a process (query) in ClickHouse?
• How to implement pivot (like in pandas)?
• How to remove the default ClickHouse user through users.d?
• Importing MySQL dump to ClickHouse
• Window function workarounds (row_number, lag/lead, running diff/sum/average) ##}

{## Original article ##}